Healthy and open fallopian tubes facilitate conception and a normal intrauterine surface without polyps, submucous myomata, septa or scars allows the normal process of implantation to occur. An endocervical canal without diverticula, a lower segment without postoperative scars or defects and a normal internal cervical os may be important to a successful pregnancy.
Hysterosalpingography (HSG) is a radiologic examination for visualizing the above-mentioned areas and is useful in diagnosing the cause(s) of infertility. The procedure consists of taking fluoroscopic x-ray films as contrast medium flows through the uterus and the fallopian tubes. Normally, when a contrast material is placed into the uterus, it will flow freely through the fallopian tubes and into the peritoneal cavity. When there is a blockage in the tubes, flow of the contrast medium is stopped.
In addition to diagnosis, HSG has therapeutic value in patients with normal tubal patency as there is an increased rate of conception following HSG procedures. HSG is also used in assisted reproductive technologies for fertility enhancement to determine that the required conditions for success exist. For example, ovarian stimulation with intrauterine insemination requires the presence of at least one open fallopian tube for success. Gamete intrafallopian transfer and zygote intrafallopian transfer require that at least one tube be open and that it be of normal caliber. HSG is also indicated in patients who have previously undergone tubal cannulation procedures to document continued patency, since transfer attempts may induce damage or scarring in the tubal lumen.
Various intrauterine injectors for use in HSG have been designed. They require that the distance between the uterine fundus and the internal cervical os be determined. This is because the injectors extend well above the internal cervical os and the tip of the injector must be trimmed or adjusted so as to minimize the chance of perforating the uterus. In addition, when the tip of the injector is in the uterine cavity, the endocervical canal and the lower uterine segment may not be outlined with contrast in its entirety. Many of the injectors require the use of a tenaculum which is placed on the anterior cervical lip. A sufficient "bite" is essential because a single-tooth tenaculum may tear through the cervical tissue if a great deal of traction is applied. The tenaculum causes spotting and bleeding when removed and is associated with a cramp when it is applied. When a tenaculum is used, it is difficult to move the patient to obtain oblique radiographic views.
The ideal intrauterine injector for delivering x-ray contrast medium into the uterus should be easily installed and not require measuring the distance between the uterine fundus and the internal cervical os, avoid uterine and cervical trauma, provide maximum delineation of the uterine cavity, have no added discomfort due to instrumentation (e.g., not require a tenaculum), allow patient maneuverability for oblique films or the like and not require that medical personnel hold the injector in place. Ideally it should be for single use to avoid transmitted infection (e.g. AIDS) as a result of inadequately sterilized instruments. Various injectors have been proposed for HSG, none of which satisfy all of the above mentioned criteria.